1. Field of the Invention
The present invention relates to multiview three-dimensional image display devices, and more particularly to multiview three-dimensional image display devices using polarizing filters and light strips.
2. Description of the Related Art
Conventional glasses-free type three-dimensional image display devices are generally classified into projection type devices and contact type devices. The projection type devices is perform a multiview image display by using a time multiplexing type Fresnel lens (See xe2x80x9cTime-Multiplexed Three-Dimensional Video Displayxe2x80x9d by A. R. Travis et. al., J. SID, V3, pp 203-205, 1995), a holographic screen (See xe2x80x9cA Multiview three-dimensional Imaging Systems with Full Color Capabilitiesxe2x80x9d by Jung-Young Son et. al., SPIE V3295), etc. The contact type devices perform a multiview image display by using a spatial multiplexing type lenticular plate (See xe2x80x9cAutostereoskopische Ruckprojections-und Flachbildschirmexe2x80x9d by R. Borner, FKT, V48, pp. 594-600, 1994), a parallax barrier plate (See xe2x80x9cAutostereoscopic Three-dimensional Display Using LCD Generated Parallax Barrierxe2x80x9d by H. Isono et. al., 12th Int. Display Research Conference, Japan, Display ""92, pp. 303-306, 1992), a slit type light source (See xe2x80x9cAn Autostereoscopic Display for Use with a Personal Computer, Proc. SPIE, V1256, pp. 156-163, 1990), etc., together with an eye tracking function. The devices have their respective advantages and disadvantages, but all of the devices have difficulties in multiviewing of the display.
Since the projection type devices project CRT display images through liquid crystal shutters separated from one another in the form of strips by the number of multiview images, a viewing zone is formed in a certain region at the front of the device, and thus, the optical gain of the devices are high and the images can be magnified. However, the size of the device is increased, and a projection lens of a large aperture diameter must be used in order to expand the viewing zone.
On the other hand, the contact type device has an advantage that the size thereof is decreased. However, the viewing zones corresponding to the right and left eyes are periodically distributed at the front of the image display element and the brightness and size thereof decrease with a distance from the center of the device. Therefore, the light gain of the device becomes low. Further, if the screen of the device is small, multiviewing is difficult and the expansion of the screen is impossible. If the size of the screen is increased, the image quality of the device is lowered. Moreover, the resolution of images from the respective viewpoints is lower than a half of the number of pixels in the device.
Therefore, the object of the present invention is to provide a multiview 3D image display device which decreases the size of system and has a high resolution of images, and which can thus improve the quality of images.
The other object of the present invention is to provide a multiview 3D image display device through which a plurality of users can view multiview 3D images.
In order to achieve the object of the present invention, the image display system comprises an image display element for alternately displaying respective images corresponding to the respective left and right eyes of one person on the column pixel lines thereon; two illuminating means disposed at the rear of the image display element for providing respective polarized lights onto the image display element, the respective polarized lights having polarizing directions different from each other by 90 degrees; and a polarizing filter disposed between the image display element and the illuminating means for separating the polarized lights from the illuminating means into respective polarized lights corresponding to the respective column pixel lines of the image display element, the respective polarized lights being illuminated onto the respective column pixel lines through the polarizing filter; wherein viewing zones corresponding to the left and right eyes are formed at the front of the image display element by the polarized lights having the different polarizing directions.
The present invention is a combination of the projection type device and the contact type device. The 3D display device according to the present invention enables a plurality of users to view multiview 3D images, including stereo images, by using a polarizing plate or a strip type white light array, where the strip type polarizers having different polarization directions from one another by 90 degrees are alternately arranged in parallel with a minimum distance therebetween, and separating the respective viewpoints of multiview images alternately arranged in pixel lines on a transparent image display panel such as an LCD panel, thus defining viewing zones.
A polarizing filter is in close contact with the image display element. A distance between the respective polarizing strips of the polarizing filter or the white light strips is the same as that between the pixels of the image display element, and the number of the strips is the same as that of the parallel pixel lines of the image display element. The polarizing filter is illuminated by two spaced illuminating lights having the same polarization direction as that of the strips directly or through transparent optical elements such as Fresnel lens of holographic screen having a size substantially equal to that of the image display element. In case of directly illuminating the polarizing filter, as in case of the white light strip, transparent optical elements such as Fresnel lens of holographic screen having a size substantially equal to that of the image display element must be overlapped at the front of the image display element. In case of using the white light strip, equally spaced illuminating lights, the number of which is the same as that of multiview images, are illuminated through a mask and a projection lens, wherein the mask is provided with equally spaced parallel rectangular openings having the same number as that of parallel pixel lines of the image display element divided by that of multiview images, so that the enlarged image of the mask is displayed on the image display element. In this case, the images of the openings on the mask must coincide with the corresponding pixel lines of the image display element.